-This is a new proposal for the Pediatric AIDS Clinical Trials Unit at the University of Puerto Rico, School of Medicine. Our main objective is to comply and collaborate with the Pediatric AIDS Clinical Trials Group Research Agenda. Through the ACTG Clinical Trials Protocols we enroll pediatric HIV infected patients and HIV-infected pregnant women to perinatal studies, contributing to the research protocols. Our unit follows the design and methods specified by each of the ACTG protocols to comply with each study requirements. In the last 4 years we have enrolled 164 patients to PACTG Protocols with an excellent retention rate. Our unit has been able to maintain a performance in the excellent range through 1995-96. Our Pediatric AIDS Program/PACTU located at the University Pediatric Hospital (UPH) has a multidisciplinary staff to serve the patient population, that consists of physicians, (pediatrics and pediatric infectious diseases), nurses, pharmacists, nutritionist and administrative and data management personnel. We are participants of the Women and Infants Transmission Study since 1989; enrolling over 50 HIV infected pregnant women per year. Our unit receives referrals of HIV infected children throughout public and private agencies and community based organizations to enter clinical trials. We evaluate an average of 58 new pediatric patients per year. We have the capability to enroll over 10 new parents per year to PACTG protocols and over 12 pregnant women to ACTG perinatal protocols. Our unit has the ability to comply with all the goals of the Pediatric AIDS Clinical Trials Group.